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1.
Huan Jing Ke Xue ; 39(3): 1180-1187, 2018 Mar 08.
Artigo em Chinês | MEDLINE | ID: mdl-29965462

RESUMO

Submerged macrophytes are an important component of aquatic ecosystems. During the growing period, submerged macrophytes can absorb nitrogen and phosphorus nutrients to reduce pollution loadings. Shoots of submerged macrophytes can also promote the adhesion of suspended substances in water, reducing the turbidity. The release of nutrients in sediments can be suppressed by its root system, and the resuspension of sediments caused by disturbance of winds and waves can also be resisted. The role of submerged macrophytes in ecological restoration of eutrophic lakes has attracted widespread attention. In 1960, the submerged plants Vallisneria natans and Potamogeton malaianus had been the dominant species in East Taihu. However after 2002, Nymphoides peltatum, Elodea nattalii, P. malaianus, etc. have gradually taken over the dominant roles along with significant elevations of nitrogen and phosphorus levels. Nutrients in water are not the only key factors causing eutrophication of water bodies; the nutrient source for submerged plant growth affect both the purification efficiency and the photosynthetic characteristics of submerged macrophytes. Excessive nitrogen and phosphorus concentrations can inhibit the photosynthetic physiological activities of submerged macrophytes, affecting the succession of aquatic vegetation. In addition, under high nutrient conditions, the competition from periphytic algae and planktonic algae may also directly poison submerged macrophytes, leading to its degradation and disappearance. Systematic studies on the regulation and photosynthetic fluorescence response mechanism of submerged macrophytes to varied nutrient loadings are helpful in revealing their relationships. The seedlings of submerged macrophyte V. natans were transplanted in a laboratory mesocosm to study the effect of nutrient loadings on its regulation of water nitrogen and phosphorus. Three nitrogen and phosphorus loadings from low, medium, and high levels derived from nitrate, ammonium, and phosphate were setup as the aquatic medium for the plant growth. Twelve harvests were carried out to determine the evolution of nutrient removal performance of V. natans. Its photosynthetic fluorescence characteristics were measured by a pulse-amplitude modulated fluorometer (Diving-PAM). Results showed that the nitrogen and phosphorus adsorption abilities of V. natans were gradually enhanced with the increase of nutrient concentrations in the range of TN ≤ 12 mg·L-1 and TP ≤ 1.0 mg·L-1. In the treatment of high nutrient concentrations (TN=12 mg·L-1 and TP=1.0 mg·L-1), the removal rates of nitrogen and phosphorus reached more than 95%. V. natans preferentially absorbed ammonium nitrogen when its concentration was high. The medium nutrient concentrations (TN:8-12 mg·L-1 and TP:0.6-1.0 mg·L-1) did not significantly affect the Fv/Fm ratio of leaves. However, the low nutrient concentrations (TN=3 mg·L-1 and TP=0.3 mg·L-1) could improve the Fv/Fm ratio of leaves and were beneficial for the growth of V. natans. The inhibition of photosynthetic activity and light tolerance were enhanced with the increase in nutrient concentrations. The photosynthetic activity of V. natans gradually recovered with no significant changes in the capacity for light harvesting, when the nutrient concentrations gradually decreased in the water. Our results indicate that the high nitrogen and phosphorus loadings indeed hamper the photosynthetic capacity, which may subsequently restrain the maintenance of the dominance of V. natans in the submerged macrophyte communities.

2.
J Breath Res ; 12(3): 036003, 2018 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-29400658

RESUMO

Existing standard techniques for erythrocyte (RBC) lifespan measurement, such as quantitation of labeling with isotopes or biotin, are cumbersome and time-consuming. Given that endogenous CO originates mainly from degraded RBCs, a team lead by Levitt developed a CO breath test to enable more efficient RBC lifespan estimation. The purpose of this study was to evaluate the reliability of Levitt's CO breath test method with our newly developed automatic instrument. RBC lifespan measurements conducted by Levitt's CO breath test method were conducted in 109 healthy subjects and 91 patients with chronic hemolytic anemia. In healthy subjects, the RBC lifespan was 126 ± 26 days, similar to values obtained with classical standard labeling methods. RBC lifespan did not differ significantly between males and females or between juveniles and adults, and did not correlate with age. To our knowledge, this datum represents an RBC lifespan average for the largest sample to date. In subjects with hemolytic anemia, RBC lifespan was 29 ± 14 days, which is significantly shorter than that of the healthy subjects (p = 0.001). Using 75 days as a cut-off, diagnostic accuracy for hemolytic anemia in the present study sample was 100%. In conclusion, the present results indicate that Levitt's CO breath test is an ideal method for human RBC lifespan measurement, and the newly developed automatic instrument is reliable and convenient for clinical practice.

3.
J Chromatogr B Analyt Technol Biomed Life Sci ; 879(22): 2113-8, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21703950

RESUMO

In this paper, polychlorinated biphenyl (PCB), organochlorine pesticide (OCP) and pyrethroid pesticides in peach was investigated by comparing their residual level in peach juice, pulps and peels using dispersive liquid-liquid microextraction based on solidification of floating organic droplet (DLLME-SFO) combined with gas chromatography-electron capture detection (GC-ECD). Extraction conditions such as the type of extractant, volume of extractant and dispersant, salt effect and extraction time were optimized. For juice samples, the linearity of the method was obtained in the range of 10-2000 ng L(-1),with determination coefficients>0.99. The limits of detection (LOD) of the method were ranged between 2.8 and 18.5 ng L(-1). For pulp and peel samples, the developed method is linear over the range assayed, 1-20 µg kg(-1),with coefficients also >0.99. The relative recoveries of compounds analyzed from juice, pulp and peel samples were in the range of 73-106% with a relative standard deviation between 2.6 and 11.8%. The proposed method was applied to the simultaneous analysis of residues in real peach juice, pulp and peel samples. As a result, there were no target analytes found in peach juices and pulps while 3.3 µg kg(-1) cyhalothrin and 3.5 µg kg(-1) fenvalerate were found in peels. The experiment results revealed that the pyrethroid residues just deposited on the peels of the fruits, but did not move into pulps and juices.


Assuntos
Fracionamento Químico/métodos , Cromatografia Gasosa/métodos , Frutas/química , Resíduos de Praguicidas/análise , Prunus/química , Bebidas/análise , Hidrocarbonetos Clorados/análise , Hidrocarbonetos Clorados/isolamento & purificação , Modelos Lineares , Micro-Ondas , Resíduos de Praguicidas/isolamento & purificação , Bifenilos Policlorados/análise , Bifenilos Policlorados/isolamento & purificação , Piretrinas/análise , Piretrinas/isolamento & purificação , Reprodutibilidade dos Testes , Sais , Sensibilidade e Especificidade
4.
J Chromatogr A ; 1218(18): 2476-82, 2011 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-21420097

RESUMO

A novel ultrasound-assisted surfactant-enhanced emulsification microextraction (UASEME) technique has been proposed by using low-density extraction solvents. In the proposed technique, Tween 80 and cyclohexane were injected into 5-mL glass test tubes with conical bottoms, containing 5.00 mL of a water sample that was located inside the ultrasonic bath. When the extraction process was finished, the glass test tube was sealed with a rubber plug and then placed upside down in a centrifuge. The finely dispersed droplets of cyclohexane collected at the conical bottom of test tube because the density of cyclohexane is less than of water, and the PAHs were concentrated in the cyclohexane. Next, 5 µL of the cyclohexane that collected at the conical bottom was removed using a 10-µL microsyringe and injected into high performance liquid chromatography coupled with fluorescence detection (HPLC-FLD) for analysis. The proposed method avoided the use of chlorinated solvents, which have been widely used as extraction solvents in a normal UASEME assay. Parameters that affected the extraction efficiency, such as the type and volume of the extraction solvent, the type and concentration of the surfactant, and the ultrasound emulsification time and salt addition, were investigated and optimised for the method. Under the optimum conditions, the enrichment factors ranged between 90 and 247. The limits of detection of the method were 0.6-62.5 ng L(-1). Good recoveries and repeatability of the method for the eleven PAHs were also obtained. The proposed UASEME technique has been demonstrated to be simple, practical and environmentally friendly for the determination of PAH residues in real water samples.


Assuntos
Fracionamento Químico/métodos , Hidrocarbonetos Policíclicos Aromáticos/análise , Sonicação/métodos , Tensoativos/química , Poluentes Químicos da Água/análise , Cromatografia Líquida de Alta Pressão , Cicloexanos/química , Concentração Osmolar , Polissorbatos/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Temperatura Ambiente
5.
Anal Bioanal Chem ; 399(5): 1901-6, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21174194

RESUMO

A method for analysis of diethofencarb and pyrimethanil in apple pulp and peel was developed by using dispersive liquid-liquid microextraction based on solidification of a floating organic droplet (DLLME-SFO) and high-performance liquid chromatography with diode-array detection (HPLC-DAD). Acetonitrile was used as the solvent to extract the two fungicides from apple pulp and peel, assisted by microwave irradiation. When the extraction process was finished, the target analytes in the extraction solvent were rapidly transferred from the acetonitrile extract to another extraction solvent (1-undecanol) by using DLLME-SFO. Because of the lower density of 1-undecanol than that of water, the finely dispersed droplets of 1-undecanol collected on the top of aqueous sample and solidified at low temperature. Meanwhile, the tiny particles of apple cooled and precipitated. Recovery was tested for a concentration of 8 µg kg⁻¹. Recovery of diethofencarb and pyrimethanil from apple pulp and peel was in the range 83.5-101.3%. The repeatability of the method, expressed as relative standard deviation, varied between 4.8 and 8.3% (n = 6). Detection limits of the method for apple pulp and peel varied from 1.2-1.6 µg kg⁻¹ for the two fungicides. Compared with conventional sample preparation, the method has the advantage of rapid speed and simple operation, and has high enrichment factors and low consumption of organic solvent.


Assuntos
Fracionamento Químico/métodos , Frutas/química , Malus/química , Fenilcarbamatos/análise , Pirimidinas/análise
6.
Zhonghua Xin Xue Guan Bing Za Zhi ; 38(6): 514-7, 2010 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-21033132

RESUMO

OBJECTIVE: To evaluate the value of human fatty acid binding protein (h-FABP) in predicting myocardial ischemia and injury in the perioperative period of cardiac surgery, we observed the dynamic changes of h-FABP in perioperative period of patients underwent coronary artery bypass grafting and ventricular septal defects repairing surgery, and evaluated the relationship of h-FABP and ischemia modified albumin (IMA), CK-MB, cTnI. METHODS: Patients underwent coronary artery bypass grafting (n=30) and ventricular septal defect repairing (n=30) surgery between February 2008 and December 2008 were included in this study. Venous blood sample was obtained at preoperative, aortic clamping, aortic unclamping of 10 min, 2 h, 6 h, 12 h, 24 h for the measurements of h-FABP, IMA, cTnI and CK-MB. RESULTS: h-FABP and IMA changed in the same way at various examined time points, h-FABP changes also paralleled cTnI and CK-MB changes, h-FABP peaked early during myocardial ischemia and injury and returned to baseline level at 2 h post myocardial ischemia and injury. Linear correlation analysis showed that the peak value of h-FABP was positively correlated with IMA, CK-MB and cTnI in both CABG group (r = 0.948, 0.964 and 0.961, P < 0.05) and in the VSD group (r = 0.986, 0.978 and 0.957). CONCLUSIONS: h-FABP is an early diagnostic parameter reflecting perioperative myocardial ischemia and injury in cardiac surgery. Quantitative h-FABP monitoring could predict the severity of myocardial ischemia and injury early during cardiac surgery.


Assuntos
Proteínas de Ligação a Ácido Graxo/sangue , Isquemia Miocárdica/diagnóstico , Miocárdio/metabolismo , Idoso , Albuminas/análise , Biomarcadores/sangue , Creatina Quinase Forma MB/sangue , Humanos , Pessoa de Meia-Idade , Isquemia Miocárdica/cirurgia , Período Perioperatório , Valor Preditivo dos Testes , Cirurgia Torácica , Troponina I/sangue
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